Conventionally, an electrostatic attraction device has been widely used to precisely control the temperature of a substrate in, e.g., a sputtering device. In a device that performs processing, e.g., film forming on an insulating substrate, such as glass, in vacuum ambience, an attraction device that attracts and holds the insulating substrate by a gradient force is widely used. Furthermore, when electrostatic attracting a substrate having an insulating film on the rear surface thereof, for example, a method of increasing the attraction voltage in order to enhance the attraction force is adopted.
In such an attraction device, the entire surface is in contact with the rear surface of the substrate on the attraction surface regardless of the attraction electrode pattern. Furthermore, the positional relationship between the attraction electrode pattern and the contact part of the rear surface of the substrate has not been addressed.
Accordingly, the resistance value or distance differs between the attraction electrode and the substrate, and the attraction condition has not been uniform.
Furthermore, in an area where an attraction electrode exists directly below the contact part between the substrate and the attraction surface, the attraction force is relatively large, and the material of the rear surface of the substrate or the surface of the attraction device peels off. The foregoing is a cause of process failure due to dust generation.
As well, the attraction force due to a residual electric charge on the attraction surface becomes uneven, the substrate vibrates during transportation thereof and breakage of the substrate may be occurred.
Moreover, the non-uniformity of the residual attraction force on the attraction surface affects the attraction condition while the process is repeated. In particular, temperature control per a substrate is inconsistent. and even when the residual attraction force is removed from the attraction surface by, for example, reverse polarity voltage application, it is difficult to completely remove the residual attraction force. Accordingly, a decrease in the reliability, such as, in the yield of the production process, has been a problem.
In order to solve such a problem, the conventional in-plane attraction force is relatively reduced so as to reduce the residual attraction force, for example, the attraction area relative to the substrate is simply reduced or the applied voltage is reduced.
However, the problem of this type of method has a problem that the attraction device cannot fully demonstrate the original attraction ability due to a decrease in the efficiency of heat transfer from the attraction surface to the substrate.
On the other hand, it is desired to suppress the dust generation due to the peel-off of the material of the rear surface of the substrate or the attraction device surface as discussed above.
Another problem is that a substrate conveyance error or a decrease in the yield of each substrate can be caused by a residual attraction force, occurred by a shortened throughput time in the production process, for example. Thus, it is also desired to perform control in a manner such that the attraction force of the attraction device is uniform.